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  • 1.
    Balador, Ali
    et al.
    SICS Swedish ICT Västerås AB, Västerås, Sweden. & Polytechnic University of Valencia, Valencia, Spain.
    Böhm, Annette
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Calafate, Carlos T.
    Polytechnic University of Valencia, Valencia, Spain.
    Cano, Juan-Carlos
    Polytechnic University of Valencia, Valencia, Spain.
    A Reliable Token-Based MAC Protocol for V2V Communication in Urban VANET2016In: 2016 IEEE 27TH ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR, AND MOBILE RADIO COMMUNICATIONS (PIMRC), Piscataway: IEEE , 2016, p. 1586-1591Conference paper (Refereed)
    Abstract [en]

    Safety applications developed for vehicular environments require every vehicle to periodically broadcast its status information (beacon) to all other vehicles, thereby avoiding the risk of car accidents in the road. Due to the high requirements on timing and reliability posed by traffic safety applications, the current IEEE 802.11p standard, which uses a random access Medium Access Control (MAC) protocol, faces difficulties to support timely and reliable data dissemination in vehicular environments where no acknowledgement or RTS/CTS (Request-to-Send/Clear-to-Send) mechanisms are adopted. In this paper, we propose the Dynamic Token-Based MAC (DTB-MAC) protocol. It implements a token passing approach on top of a random access MAC protocol to prevent channel contention as much as possible, thereby improving the reliability of safety message transmissions. Our proposed protocol selects one of the neighbouring nodes as the next transmitter; this selection accounts for the need to avoid beacon lifetime expiration. Therefore, it automatically offers retransmission opportunities to allow vehicles to successfully transmit their beacons before the next beacon is generated whenever time and bandwidth are available. Based on simulation experiments, we show that the DTB-MAC protocol can achieve better performance than IEEE 802.11p in terms of channel utilization and beacon delivery ratio for urban scenarios.

  • 2.
    Balador, Ali
    et al.
    Halmstad University, School of Information Technology. Universitat Politecnica de València, València, Spain.
    Böhm, Annette
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Uhlemann, Elisabeth
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES). Mälardalen University, Västerås, Sweden.
    Calafate, Carlos T.
    Universitat Politecnica de València, València, Spain.
    Cano, Juan-Carlos
    Universitat Politecnica de València, València, Spain.
    A Reliable Token-Based MAC Protocol for Delay Sensitive Platooning Applications2015In: 2015 IEEE 82nd Vehicular Technology Conference (VTC2015-Fall), [S.l.]: IEEE, 2015, article id 7390813Conference paper (Refereed)
    Abstract [en]

    Platooning is both a challenging and rewarding application. Challenging since strict timing and reliability requirements are imposed by the distributed control system required to operate the platoon. Rewarding since considerable fuel reductions are possible. As platooning takes place in a vehicular ad hoc network, the use of IEEE 802.11p is close to mandatory. However, the 802.11p medium access method suffers from packet collisions and random delays. Most ongoing research suggests using TDMA on top of 802.11p as a potential remedy. However, TDMA requires synchronization and is not very flexible if the beacon frequency needs to be updated, the number of platoon members changes, or if retransmissions for increased reliability are required. We therefore suggest a token-passing medium access method where the next token holder is selected based on beacon data age. This has the advantage of allowing beacons to be re-broadcasted in each beacon interval whenever time and bandwidth are available. We show that our token-based method is able to reduce the data age and considerably increase reliability compared to pure 802.11p. © 2015 IEEE.

  • 3.
    Balador, Ali
    et al.
    Polytechnic University of Valencia, Valencia, Spain.
    Böhm, Annette
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Uhlemann, Elisabeth
    Mälardalen University, Västerås, Sweden.
    Calafate, Carlos T.
    Polytechnic University of Valencia, Valencia, Spain.
    Ji, Yusheng
    National Institute of Informatics, Tokyo, Japan.
    Cano, Juan-Carlos
    Polytechnic University of Valencia, Valencia, Spain.
    Manzoni, Pietro
    Polytechnic University of Valencia, Valencia, Spain.
    An Efficient MAC Protocol for vehicle platooning in automated highway systems2015Conference paper (Refereed)
    Abstract [en]

    Lately, all the top truck manufacturers are investing considerable resources in the research and development of platooning systems which would allow vehicles to save fuel and improve safety by travelling in a close-following manner. The platooning system requires frequent and reliable vehicle-to-vehicle communications. As platooning takes place in a vehicular ad hoc network, the use of IEEE 802.11p is close to mandatory. However, the 802.11p medium access method suffers from packet collisions and random delays. Most ongoing research suggests using TDMA on top of 802.11p as a potential remedy. However, TDMA requires synchronization and is not very flexible if the beacon frequency needs to be updated, the number of platoon members changes, or if re-transmissions for increased reliability are required. We therefore suggest a token-passing medium access method where the next token holder is selected based on beacon data age. This has the advantage of allowing beacons to be re-broadcasted in each beacon interval whenever time and bandwidth are available. We show that our token-based method is able to reduce the data age and considerably increase reliability considerably compared to pure 802.11p.

  • 4.
    Bilstrup, Katrin
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Böhm, Annette
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Lidström, Kristoffer
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Larsson, Tony
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Strandén, Lars
    SP Technical Research Institute of Sweden, Borås, Sweden.
    Zakizadeh, Hossein
    Volvo Technology Corporation, Göteborg, Sweden .
    Vehicle Alert System2007In: Proceedings of 14th world congress on intelligent transport system (ITS), 2007, p. 2-9Conference paper (Refereed)
    Abstract [en]

    The Vehicle Alert System (VAS) project focuses on cooperative alert services based on timely and reliable communication under the challenging circumstances pertaining to a highly mobile vehicular network. Through a cross-layer design, we gain the flexibility needed to adapt the system to the individual requirements of three chosen application scenarios that represent different situations where cooperation between vehicles can make a significant impact. The VAS project is a collaboration involving academic as well as industrial partners and the final stage of the project is a demonstrator that implements results from the research.

  • 5.
    Bilstrup, Katrin
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Böhm, Annette
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Lidström, Kristoffer
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Larsson, Tony
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Uhlemann, Elisabeth
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Report on the Collaboration between CVIS and CERES in the Project Vehicle Alert System (VAS)2009Report (Other academic)
    Abstract [en]

    In March 2007, an agreement was made for interchange of experiences between CVIS and the Centre for Research on Embedded Systems (CERES) at Halmstad University in Sweden. The majority of the work relating to this collaboration has been conducted within the CERES project Vehicle Alert System (VAS), aiming to use vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications to provide different types of warning messages. The main focus of the VAS project is on communication and in particular the lower layers of the communication stack are investigated. VAS involves academic researchers from Halmstad University as well as researchers from Volvo Technology, SP Technical Research Institute of Sweden and the company Free2move. This report presents the results of the VAS project, its publications, and other issues of interest both to the CVIS consortium as well as a broader scope.

  • 6.
    Böhm, Annette
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Delay-sensitive wireless communication for cooperative driving applications2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Cooperative driving holds the potential to considerably improve the level of safety and efficiency on our roads. Recent advances in in-vehicle sensing and wireless communication technology have paved the way for the development of cooperative traffic safety applications based on the exchange of data between vehicles (or between vehicles and road side units) over a wireless link. The access to up-to-date status information from surrounding vehicles is vital to most cooperative driving applications. Other applications rely on the fast dissemination of warning messages in case a hazardous event or certain situation is detected. Both message types put high requirements on timeliness and reliability of the underlying communication protocols.

    The recently adopted European profile of IEEE 802.11p defines two message types,periodic beacons for basic status exchange and event-triggered hazard warnings, both operating at pre-defined send rates and sharing a common control channel. The IEEE 802.11p Medium Access Control (MAC) scheme is a random access protocol that doesnot offer deterministic real-time support, i.e. no guarantee that a packet is granted access to the channel before its deadline can be given. It has been shown that a high number of channel access requests, either due to a high number of communicating vehicles or highdata volumes produced by these vehicles, cannot be supported by the IEEE 802.11p MAC protocol, as it may result in dropped packets and unbounded delays.

    The goal of the work presented in this thesis has therefore been to enhance IEEE 802.11p without altering the standard such that it better supports the timing and reliability requirements of traffic safety applications and provides context-aware andefficient use of the available communication resources in a vehicular network. The proposed solutions are mapped to the specific demands of a set of cooperative driving scenarios (featuring infrastructure-based and infrastructure-free use cases, densely and sparsely trafficked roads, very high and more relaxed timing requirements) and evaluated either analytically, by computer simulation or by measurements and compared to the results produced by the unaltered IEEE 802.11p standard.

    As an alternative to the random MAC method of IEEE 802.11p, a centralized solution isproposed for application scenarios where either a road side unit or a suitable dedicated vehicle is present long enough to take the coordinating role. A random access phase forevent-driven data traffic is interleaved with a collision-free phase where timely channel access of periodic delay-sensitive data is scheduled. The ratio of the two phases isdynamically adapted to the current data traffic load and specific application requirements. This centralized MAC solution is mapped on two cooperative driving applications: merge assistance at highway entrances and platooning of trucks. Further,the effect of a context-aware choice of parameters like send rate or priority settings based on a vehicle’s position or role in the safety application is studied with the goal to reduce the overall number of packets in the network or, alternatively, use the available resources more efficiently. Examples include position-based priorities for the merge assistance use case, context-aware send rate adaptation of status updates in anovertaking warning application targeting sparsely-trafficked rural roads and an efficient dissemination strategy for warning messages within a platoon.

    It can be concluded that IEEE 802.11p as is does not provide sufficient support for the specific timing and reliability requirements imposed by the exchange of safety-criticalreal-time data for cooperative driving applications. While the proper, context-awarechoice of parameters, concerning send rate or priority level, within the limits of the standard, can lead to improved packet inter-arrival rates and reduced end-to-end delays,the added benefits from integrating MAC solutions with real-time support into the standard are obvious and needs to be investigated further.

  • 7.
    Böhm, Annette
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    State of the Art on Energy-Efficient and Latency-Constrained Networking Protocols for Wireless Sensor Networks2007Report (Other academic)
    Abstract [en]

    Advances in the development and integration of small battery-powered sensing devices have enabled the design of applications where a group of sensors cooperate in monitoring their environment. Wireless sensor networks (WSN) are today used in a wide variety of areas like e.g. habitat monitoring, battle field surveillance, disaster management, health monitoring or industrial control. Their applicability is often reduced by limitations in the sensor nodes power supply, communication bandwidth, processing capabilities and buffer size. Many researchers have put effort in overcoming these shortcomings, with a special focus on maximizing the battery lifetime of a single node as well as the lifetime of the network as a whole. A list of possible applications can be found in [Akyildiz].

    As applications become more and more mission-critical, it is crucial that the collected sensor data arrive at the sink within a specified time limit. Guaranteeing a certain quality of service (QoS) to a user or an application is difficult because of the unpredictable nature of the wireless link and the often unstable topology of the sensor network (due to node failure or mobility). Very little research has been done in the field of QoS for WSNs [Chen] [Wang] and many interesting research questions are still unanswered.

    This state-of-the-art document aims at giving an overview on routing and medium access issues in WSNs and at summarizing some of the most interesting solutions. The requirements on WSN protocols are very dependent on the application in which the WSN will be used. Aspects as energy-efficiency, latency, Quality of Service (QoS), mobility, distribution density or cost all influence the choice of protocol and its parameters. There is therefore no single protocol that matches all types of WSN and the best results can only be achieved by tailoring the protocol for a specific application or scenario.

    In this state-of-the-art report, we make certain assumptions, loosely based upon the requirements of a surveillance application.

  • 8.
    Böhm, Annette
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    State of the art on network layer aspects for inter-vehicle communication2007Report (Other academic)
    Abstract [en]

    In future vehicular networks, the amount of help a driver can get in avoiding dangerous traffic situations or minimizing the potential damage will increase dramatically. Information about weather and road conditions, digital maps and navigation systemsare combined with sensor data from the own vehicle as well as surrounding vehicles. Fast and reliable communication between cars (vehicle-to-vehicle) and/or between a car and a road side unit (vehicle-to-infrastructure) are essential for future vehicle alert systems.

    From a network perspective, this means that messages have to be routed from the information source to one or several destinations without too much administrative overhead and delay. Fast topology changes and high mobility in a vehicular networkneed to be considered when developing new routing protocols. In vehicle-to-infrastructure communication, vehicles enter and leave the transmission range ofroadside units at a fast pace and handover techniques need to be adapted in order tomaintain connectivity. The motivation for many of the current approaches is to providethe driver and/or passengers in a vehicle with the quality of service needed formultimedia applications but the ideas behind fast and seamless communication canlikewise be the basis for future vehicle safety application.This report gives a short survey over the work that has been done on adapting multi-hop routing and handover techniques to a vehicular network environment and explainssome of the ideas behind the proposed solutions.

  • 9.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Handover in IEEE 802.11p-based delay-sensitive vehicle-to-infrastructure communication2009Report (Other academic)
    Abstract [en]

    Based on communication and cooperation between vehicles and roadside infrastructure, Intelligent Transport Systems (ITS) safety applications offer great potential to avoid traffic accidents or at least reduce their impact. As these applications usually are delay-sensitive, the delay introduced by waiting for access to the wireless communication channel should both be reduced and provided with an upper bound. The proposed IEEE 802.11p standard for short to medium range vehicular communication does not offer these guarantees. In previous work, we presented a MAC (Medium Access Control) enhancement supporting delay-sensitive, safety-critical V2I (Vehicle-to-Infrastructure) applications. Since the proposed enhancement requires a deterministic and fast mechanism to associate a vehicle to a roadside unit (RSU) so that it can be integrated into the centralized polling schedule, we now target the handover and connection setup between a vehicle and an RSU. Although the first connection setup with an RSU still underlies the randomness of the original 802.11p MAC method, we provide a deterministic solution to further enhance the handover procedures by introducing a fast, proactive handover mechanism. We show that the overhead of our solution is limited and still allows our MAC protocol to support safety-critical V2I applications in a densely trafficked highway scenario.

  • 10.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Position-based data traffic prioritization in safety-critical, real-time vehicle-to-infrastructure communication2009In: IEEE International Conference on Communications Workshops, 2009. ICC Workshops 2009 / [ed] IEEE, Piscataway, N.J.: IEEE Press, 2009, p. 205-210Conference paper (Refereed)
    Abstract [en]

    Future active-safety applications in vehicular networks rely heavily on the support for real-time inter-vehicle communication. The Medium Access Control (MAC) mechanism proposed for the upcoming IEEE 802.11p standard intended for Intelligent Transport Systems (ITS) applications does not offer deterministic real-time support, i.e., the channel access delay is not upper bounded. We therefore propose a vehicle-to-infrastructure (V2I) communication solution extending IEEE 802.11p, by introducing a collision-free MAC phase with an enhanced prioritization mechanism based on vehicle positions and the overall road traffic density. A road side unit using a polling mechanism is then able to provide real-time support such that it can guarantee collision-free channel access within its transmission range. Part of the bandwidth remains unchanged such that best-effort services like ongoing vehicle-to-vehicle (V2V) applications may continue. Our solution guarantees that all communication deadlines of the V2I applications are met, while minimizing the required length of the collision-free phase. This in turn maximizes the amount of bandwidth available for best-effort services and ongoing V2V applications. The position-based prioritization mechanism further improves the throughput of both real-time and best-effort data traffic by focusing the communication resources to the most hazardous areas. The concept is evaluated analytically based on a realistic task set from a V2I merge assistance scenario.

  • 11.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Position-based forwarding techniques for vehicular ad-hoc networks2008In: Proceedings of Swedish National Computer Networking Workshop (SNCNW 2008), 2008Conference paper (Refereed)
  • 12.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Position-based real-time communication support for cooperative traffic safety services2011Conference paper (Refereed)
    Abstract [en]

    Future cooperative traffic safety applications based on vehicular networks rely heavily on the support for real-time inter-vehicle communication. The Medium Access Control (MAC) mechanism proposed for the upcoming IEEE 802.11p standard intended for Intelligent Transport Systems (ITS) applications does not offer deterministic real-time support, i.e., the channel access delay is not upper bounded. In this paper, we therefore propose a vehicle-to-infrastructure(V2I) communication solution extending IEEE802.11p by introducing a collision-free MAC phase based on real-time schedulability analysis. A static or semi-static access point on the road side (Road Side Unit, RSU) coordinates the vehicles’ access to the communication medium by polling them for data according to a schedule based on the Earliest Deadline First (EDF) principle. It is thereby possible to provide real-time support such that the access point can guarantee collision-free channel access within its transmission range. Part of the bandwidth remains unchanged and best-effort services like ongoing vehicle-to-vehicle (V2V) applications can continue. We enhance our MAC solution by introducing a prioritization mechanism based on vehicle positions and the overall road traffic density, which leads to a more efficient use of the available bandwidth and further improves the real-time capabilities of our solution.

  • 13.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Real-Time Communication in Infrastructure-Based Safety-Critical Information Exchange2008In: 15th World Congress on Intelligent Transport Systems: New York, November 16-20, 2008 : proceedings : ITS connections: saving time, saving lives / [ed] ITS America, Ertico, ITS Japan, 2008Conference paper (Refereed)
  • 14.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Real-time communication support for cooperative, infrastructure-based traffic safety applications2011In: International Journal of Vehicular Technology, ISSN 1687-5702, E-ISSN 1687-5710, Vol. 2011, no Article ID 541903, p. 17-Article in journal (Refereed)
    Abstract [en]

    The implementation of ITS (Intelligent Transport Systems) services offers great potential to improve the level of safety, efficiency and comfort on our roads. Although cooperative traffic safety applications rely heavily on the support for real-time communication, the Medium Access Control (MAC) mechanism proposed for the upcoming IEEE 802.11p standard, intended for ITS applications, does not offer deterministic real-time support, that is, the access delay to the common radio channel is not upper bounded. To address this problem, we present a framework for a vehicle-to-infrastructure-based (V2I) communication solution extending IEEE 802.11p by introducing a collision-free MAC phase assigning each vehicle an individual priority based on its geographical position, its proximity to potential hazards and the overall road traffic density. Our solution is able to guarantee the timely treatment of safety-critical data, while minimizing the required length of this real-time MAC phase and freeing bandwidth for best-effort services (targeting improved driving comfort and traffic efficiency). Furthermore, we target fast connection setup, associating a passing vehicle to an RSU (Road Side Unit), and proactive handover between widely spaced RSUs. Our real-time MAC concept is evaluated analytically and by simulation based on a realistic task set from a V2I highway merge assistance scenario.

  • 15.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Supporting real-time data traffic in safety-critical vehicle-to-infrastructure communication2008In: 33rd IEEE Conference on Local Computer Networks, 2008. LCN 2008, Los Alamitos: IEEE Computer Society, 2008, p. 614-621Conference paper (Refereed)
    Abstract [en]

    Support for real-time traffic is crucial to many ITS (Intelligent Transport Systems) safety applications. At the same time it is desirable to provide a number of non-safety services. In this paper, we propose a communication system for safety-critical V2I (Vehicle-to-Infrastructure) communication based on an extension to the upcoming IEEE 802.11p MAC standard. Real-time analysis provides the tool to adapt the resources set aside for collision-free, safety-critical data traffic to the communication needs of the current number of supported vehicles. The remaining bandwidth is available to other services according to the contention-based random access method defined in the standard. The performance of the proposed concept is evaluated through a simulation analysis based on a merge assistance scenario supported by roadside infrastructure.

  • 16.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Kunert, Kristina
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    A fibre-optic AWG-based real-time network for high-performance embedded computing2004Conference paper (Refereed)
    Abstract [en]

    In this paper, an architecture and a Medium Access Control (MAC) protocol for a multiwavelength optical communication network, applicable in short range communication systems like System Area Networks (SANs), are proposed. The main focus lies on guaranteed support for hard and soft real-time traffic. The network is based upon a single-hop star topology with an Arrayed Waveguide Grating (AWG) at its center. Traffic scheduling is centralized in one node (residing together with the AWG in a hub), which communicates through a physical control channel. The AWG’s property of spatial wavelength reuse and the combination of fixedtuned and tunable transceivers in the nodes enable simultaneous control and data transmission. A case study with defined real-time communication requirements in the field of Radar Signal Processing (RSP) was carried out and indicates that the proposed system is very suitable for this kind of application.

  • 17.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Kunert, Kristina
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    AWG-based Optoelectronic Router with QoS Support2005In: 2005 International Conference on Wireless and Optical Communications Networks: March 6 - 8, 2005, Dubai, United Arab Emirates, Piscataway, NJ: IEEE Press, 2005, p. 23-28Conference paper (Refereed)
    Abstract [en]

    We present a router architecture with electronic queuing and a passive optical multi-channel network, which is based upon a single-hop star topology with an arrayed waveguide grating (AWG) at its center. The AWG's property of spatial wavelength reuse and both fixed-tuned and tunable transceivers enable simultaneous control and data transmission. Our proposed medium access control protocol supports traffic differentiation and utilizes EOF (earliest deadline first) to schedule the traffic from input ports to output ports on the router. Our simulations show that the router treats QoS (quality of service) traffic well.

  • 18.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Jonsson, Magnus
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Kunert, Kristina
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Hoang, Hoai
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    A Fibre-Optic AWG-Based Real-Time Network and Its Applicability to High-Performance Embedded Computing2005In: 19th International Parallel and Distributed Processing Symposium: proceedings, Piscataway, N.J.: IEEE Press, 2005, p. 133b-133b, article id 1419972Conference paper (Refereed)
    Abstract [en]

    In this paper, an architecture and a Medium Access Control (MAC) protocol for a multi-wavelength optical communication network, applicable in short range communication systems like System Area Networks (SANs), are proposed. The main focus lies on guaranteed support for hard and soft real-time traffic. The network is based upon a single-hop star topology with an Arrayed Waveguide Grating (AWG) at its center. Traffic scheduling is centralized in one node (residing together with the AWG in a hub), which communicates through a physical control channel. The AWG's property of spatial wavelength reuse and the combination of fixed-tuned and tunable transceivers in the nodes enable simultaneous control and data transmission. A case study with defined real-time communication requirements in the field of Radar Signal Processing (RSP) was carried out and indicates that the proposed system is very suitable for this kind of application.

  • 19.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Kunert, Kristina
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Vinel, Alexey
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Context-Aware Retransmission Scheme for Increased Reliability in Platooning Applications2014In: Communication Technologies for Vehicles: 6th International Workshop, Nets4Cars/Nets4Trains/Nets4Aircraft 2014, Offenburg, Germany, May 6-7, 2014. Proceedings, Cham: Springer, 2014, p. 30-42Conference paper (Refereed)
    Abstract [en]

    Recent advances in cooperative driving hold the potential to significantly improve safety, comfort and efficiency on our roads. An application of particular interest is platooning of vehicles, where reduced inter-vehicle gaps lead to considerable reductions in fuel consumption. This, however, puts high requirements on timeliness and reliability of the underlying exchange of control data. Considering the difficult radio environment and potentially long distances between communicating platoon members, as well as the random channel access method used by the IEEE 802.11p standard for short-range inter-vehicle communication, those requirements are very difficult to meet. The relatively static topology of a platoon, however, enables us to preschedule communication within the platoon over a dedicated service channel. Furthermore, we are able to set aside parts of the available bandwidth for retransmission of packets in order to fulfil the reliability requirements stated by the platoon control application. In this paper, we describe the platooning framework along with the scheduling algorithm used to assign retransmission slots to control packets that are most likely to need them. This retransmission scheduling scheme offers a valuable tool for system designers when answering questions about the number of safely supported vehicles in a platoon, achievable reductions in inter-vehicle gaps and periodicity of control packets. © 2014 Springer International Publishing.

  • 20.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Uhlemann, Elisabeth
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Adaptive Cooperative Awareness Messaging for Enhanced Overtaking Assistance on Rural Roads2011In: IEEE Vehicular Technology Conference (VTC Fall 2011), Piscataway, N.J.: IEEE Press, 2011, p. 1-5Conference paper (Refereed)
    Abstract [en]

    Cooperative traffic safety applications such as lane change or overtaking assistance have the potential to reduce the number of road fatalities. Many emerging traffic safety applications are based on IEEE 802.11p and periodic position messages, so-called cooperative awareness messages (CAM) being broadcasted by all vehicles. In Europe, ETSI defines a periodic report rate of 2 Hz for CAMs. Although a high report rate is the key to early hazard detection, the 2 Hz rate has been chosen to avoid congestion in settings where the vehicle density is high, e.g., on major highways and in urban scenarios. However, on rural roads with a limited number of communicating vehicles, a report rate of 2 Hz leads to unnecessary delay in cooperative awareness. By adapting the CAM report rate depending on the specific application and road traffic density, and by making use of the priority levels provided by the 802.11p quality of service mechanism, we show that hazards can be detected earlier and the available bandwidth is used more efficiently, while not overexploiting the network resources.

  • 21.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Uhlemann, Elisabeth
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Co-existing periodic beaconing and hazard warnings in IEEE 802.11p-based platooning applicationsManuscript (preprint) (Other academic)
    Abstract [en]

    A platoon of trucks driving at the same, mutually agreed speed while keeping a minimum inter-vehicle distance will reduce fuel consumption, enhance transport efficiency as well as improve the safety of other adjacent road users. The European profile of IEEE 802.11p for inter-vehicle communications uses a single 10 MHz control channel dedicated to safety-critical data, shared by periodic status updates, CAM (Cooperative Awareness Message), and event-triggered warnings, DENM (Decentralized Environmental Notification Message). Coupled with the random access delay inherent to the 802.11p medium access method, the strict timing and reliability requirements of platoon applications are not easily met. To this end, we evaluate by simulation the effect of IEEE 802.11p-compliant send rate adaptations and message type prioritizations and the choice of warning dissemination strategy on CAM transmissions and DENM dissemination in a platooning scenario. Simulation studies of a platoon of 10-20 vehicles in a busy highway scenario show that the context-aware choice of send rate, priority class and dissemination strategy not only reduce the dissemination delay of DENMs but even has a significant effect on the throughput of CAMs exchanged by platoon members.

  • 22.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Uhlemann, Elisabeth
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Co-Existing Periodic Beaconing and Hazard Warnings in IEEE 802.11p-Based Platooning Applications2013In: VANET 2013 - Proceedings of the 10th ACM International Workshop on VehiculAr Inter-NETworking, Systems, and Applications, New York, NY: ACM Press, 2013, p. 99-101Conference paper (Refereed)
    Abstract [en]

    A platoon of trucks driving at the same, mutually agreed speed while keeping a minimum inter-vehicle distance will reduce fuel consumption, enhance transport efficiency as well as improve the safety of other adjacent road users. The European profile of IEEE 802.11p for inter-vehicle communications uses a single 10 MHz control channel dedicated to safety-critical data, shared by periodic status updates, and event-triggered warnings. Coupled with the random access delay inherent to the 802.11p medium access method, the strict timing and reliability requirements of platoon applications are not easily met. To this end, we evaluate the effect of IEEE 802.11p-compliant send rate adaptations and message type prioritizations and the choice of warning dissemination strategy in a platooning scenario. Simulation studies of a platoon of 10-20 vehicles in a busy highway scenario show that a context-aware choice of send rate, priority class and dissemination strategy not only reduces the hazard warning dissemination delay but also has a significant effect on the throughput of periodic beacons.

  • 23.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Uhlemann, Elisabeth
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Performance comparison of a platooning application using the IEEE 802.11p MAC on the control channel and a centralized MAC on a service channel2013In: 2013 IEEE 9th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), Piscataway, NJ: IEEE Press, 2013, p. 545-552, article id 6673411Conference paper (Refereed)
    Abstract [en]

    Recent advances in cooperative driving hold the potential to significantly improve safety, comfort and efficiency on our roads. An application of particular interest is platooning of trucks, where it has been shown that keeping a minimum inter-vehicle distance results in considerably reduced fuel consumption.This, however, puts high requirements on timeliness and reliability of the underlying exchange of control messages betweenplatoon members. The European profile of IEEE 802.11p, recently adopted by ETSI, defines two message types to this end, periodic beacons for basic cooperative awareness (CAM) and event-triggered decentralized environmental notification messages (DENM), both of which will use one common control channel. IEEE 802.11p employs a random medium access protocol, which may experience excessive delays during high network loads. To mitigate these effects, ETSI standardizes a decentralized congestion control algorithm to, e.g., lower the CAM update frequency during high loads. However, this may prevent proper functionality of a platooning application. In this paper we propose a solution that instead uses a dedicated service channel for platooning applications and compare its performance to standard-compliant IEEE 802.11p inter-platoon communication on the control channel. Service channels typically have less strict requirements on send rates, data traffic types and medium access methods. Our service channel solution combines a random access phase for DENM with a centralized, scheduled access phase for CAM. Using a service channel enables us to guarantee timely channel access for all CAM packets before a specified deadline while still being able to provide a reasonable DENM dissemination delay. © 2013 IEEE.

  • 24.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Uhlemann, Elisabeth
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Performance evaluation of a platooning application using the IEEE 802.11p MAC on a control channel vs. a centralized real-time MAC on a service channelManuscript (preprint) (Other academic)
    Abstract [en]

    Recent advances in cooperative driving hold the potential to significantly improve safety, comfort and efficiency on our roads. An application of particular interest is platooning of trucks, where it has been shown that keeping a minimum inter-vehicle distance results in considerably reduced fuel consumptions. This, however, puts high requirements on timeliness and reliability of the underlying exchange of control messages between platoon members. The European profile of IEEE 802.11p, recently adopted by ETSI, defines two message types to this end, periodic beacons for basic cooperative awareness (CAM) and event-triggered decentralized environmental notification messages (DENM), both using the common control channel. The IEEE 802.11p employs a random medium access protocol, with excessive delays that may prevent proper functionality of a platooning application. To mitigate the effects of this, ETSI standardizes a decentralized congestion control algorithm to, e.g., lower the CAM frequency when needed. Some service channels with less strict requirements on send rates, data traffic types or medium access methods are available. In this paper we compare the performance of decentralized, standard-compliant inter-platoon communication using IEEE 802.11p on the control channel with a solution based on a service channel, which combines a random access phase for DENM with a centralized, scheduled access phase for CAM. A dedicated service channel for platooning applications enables us to always guarantee timely channel access of CAM packets before a specified deadline and our simulations show that this is achieved at very small sacrifices in DENM dissemination delay.

  • 25.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Zakizadeh, Hossein
    Volvo Technology.
    Vehicular ad-hoc networks to avoid surprise effects on sparsely trafficked, rural roads2011Conference paper (Refereed)
    Abstract [en]

    This paper summarizes the main results from a project focusing on the development and evaluation of communication protocols for inter-vehicle communication on sparsely trafficked, rural roads,ensuring the reliable and timely delivery of safety critical data. The project is motivated by traffic safety applications, especially warning systems to avoid surprise effects of unexpected vehicle encounters on sparsely-trafficked, rural roads. The key issue in suchan application is to make sure that the vehicles become aware of each other’s existence by the help of communication as soon as possible. The driver can then be warned in time to avoid a possible accident.The challenge is to gain high probabilities of successful delivery in time, especially when having to cope with bad communication performance caused by e.g. crests.

  • 26.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Kunert, Kristina
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Data age based MAC scheme for fast and reliable communication within and between platoons of vehicles2016In: International Conference on Wireless and Mobile Computing, Networking and Communications, Piscataway: IEEE, 2016Conference paper (Refereed)
    Abstract [en]

    Heavy vehicles driving as platoon with highly reduced inter-vehicle gaps has shown considerable fuel saving potential, but put high timing and reliability requirements on the underlying control data exchange. The recently standardized IEEE 802.11p protocol suite for Vehicular Ad-Hoc Networks (VANETs) and its message types do neither support the demands of a platooning application nor take advantage of its properties. We therefore propose a framework for centralized channel access with retransmission capabilities for safety critical control data exchange based on the data age of earlier received messages, DA-RE (Data Age based REtransmission scheme). A simulation comparison to the 802.11p random access Medium Access Control (MAC) protocol shows that the intelligent assignment of retransmission opportunities considerably improves the reliability of platooning control data. We also propose a power control based scheme for early platoon detection allowing several platoons to temporarily share a channel and show that the safe and reliable operation of their vehicles is not compromised. © 2016 IEEE.

  • 27.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Kunert, Kristina
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Data age based retransmission scheme for reliable control data exchange in platooning applications2015In: 2015 IEEE International Conference on Communication Workshop (ICCW), Piscataway, NJ: IEEE Press, 2015, p. 2412-2418Conference paper (Refereed)
    Abstract [en]

    Recent advances in cooperative driving hold the potential to significantly improve safety, comfort and efficiency on our roads. Platooning of heavy vehicles, where automated or semi-automated driving allows minimal inter-vehicle gaps, has shown considerable reductions in fuel consumption. Although using the same wireless communication technology, a platoon differs from a VANET (Vehicular Ad-hoc NETwork) in several points. It is centralized in its nature, with a well-defined group leader, its topology is fairly stable and it has very challenging requirements on timeliness and reliability of its control data exchange. Therefore, the IEEE 802.11p protocol suite and its recently defined message types do neither support the needs of a platooning application nor take advantage of its properties. A platoons control loop must continuously be fed with fresh data, so the information age is an important parameter to be closely monitored. In this paper, we therefore propose a framework for centralized channel access and retransmission capabilities for safety critical inter-platoon control data based on the data age of earlier received messages. A simulation evaluation compares our solution to a) the decentralized, standard-compliant IEEE 802.11p MAC (Medium Access Control) method, and a time-slotted scheme b) with and c) without retransmissions and shows that the centralized, data age based retransmission scheme clearly outperforms its competitors in terms of maintained data age. © 2015 IEEE.

  • 28.
    Böhm, Annette
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Lidström, Kristoffer
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Larsson, Tony
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Evaluating CALM M5-based vehicle-to-vehicle communication in various road settings through field trials2010In: Proceedings - Conference on Local Computer Networks, LCN, (2010 12 01): 613-620, Piscataway, N.J.: IEEE Press, 2010, p. 613-620Conference paper (Refereed)
    Abstract [en]

    Future cooperative Intelligent Transport Systems (ITS) applications aimed to improve safety, efficiency and comfort on our roads put high demands on the underlying wireless communication system. To gain better understanding of the limitations of the 5.9 GHz frequency band and the set of communication protocols for medium range vehicle to vehicle (V2V) communication, a set of field trials with CALM M5 enabled prototypes has been conducted. This paper describes five different real vehicle traffic scenarios covering both urban and rural settings at varying vehicle speeds and under varying line-of-sight (LOS) conditions and discusses the connectivity (measured as Packet Reception Ratio) that could be achieved between the two test vehicles. Our measurements indicate a quite problematic LOS sensitivity that strongly influences the performance of V2V-based applications. We further discuss how the awareness of these context-based connectivity problems can be used to improve the design of possible future cooperative ITS safety applications.

  • 29.
    Jonsson, Magnus
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Kunert, Kristina
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Böhm, Annette
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Increased communication reliability for delay-sensitive platooning applications on top of IEEE 802.11p2013In: Communication Technologies for Vehicles: 5th International Workshop, Nets4Cars/Nets4Trains 2013, Villeneuve d’Ascq, France, May 14-15, 2013. Proceedings / [ed] Marion Berbineau, Magnus Jonsson, Jean-Marie Bonnin, Soumaya Cherkaoui, Marina Aguado, Cristina Rico-Garcia, Hassan Ghannoum, Rashid Mehmood, Alexey Vinel, Heidelberg: Springer Berlin/Heidelberg, 2013, p. 121-135Conference paper (Refereed)
    Abstract [en]

    Cooperative driving in platooning applications has received much attention lately due to its potential to lower fuel consumption and improve safety and efficiency on our roads. However, the recently adopted standard for vehicular communication, IEEE 802.11p, fails to support the level of reliability and real-time properties required by highly safety-critical applications. In this paper, we propose a communication and real-time analysis framework over a dedicated frequency channel for platoon applications and show that our retransmission scheme is able to decrease the message error rate of control data exchange within a platoon of moderate size by several orders of magnitude while still guaranteeing that all delay bounds are met. Even for long platoons with up to seventeen members the message error rate is significantly reduced by retransmitting erroneous packets without jeopardizing the timely delivery of regular data traffic. © 2013 Springer-Verlag.

  • 30.
    Jonsson, Magnus
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Kunert, Kristina
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Böhm, Annette
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Increasing the probability of timely and correct message delivery in road side unit based vehicular communication2012In: IEEE Conference Intelligent Transportation Systems (ITSC), 2012 15th International Conference, Piscataway: IEEE Press, 2012, p. 672-679Conference paper (Refereed)
    Abstract [en]

    Intelligent transport systems provide a multitude of possibilities when it comes to increasing traffic safety on our roads. Many of the proactive traffic safety applications under development today demand timely and reliable treatment of deadline dependent data traffic. Unfortunately it is not possible to provide any timing guarantees when using the current IEEE 802.11p standard for wireless access in vehicular environments. Additionally, a difficult wireless channel environment makes successful data transmissions very challenging. We suggest adding a real-time layer, comprising a deterministic medium access control protocol and transport layer retransmissions, on top of IEEE 802.11p in order to enable guaranteed real-time behaviour and to improve reliability. In a simulation study we show that the packet error rate can be decreased by several orders of magnitude while being able to guarantee timely treatment of both ordinary transmissions and retransmissions by the help of a real-time schedulability analysis.

  • 31.
    Kunert, Kristina
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Böhm, Annette
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    AWG-based optoelectronic router supporting both guaranteed and best-effort QoS traffic2005Conference paper (Refereed)
    Abstract [en]

    We present a router architecture with electronic queuing and a passive optical multi-channel network, based upon a single-hop star topology with an Arrayed Waveguide Grating (AWG) at its centre. The AWG’s property of spatial wavelength reuse and both fixed-tuned and tuneable transceivers enable simultaneous control and data transmission. Our proposed medium access control protocol supports traffic differentiation and utilizes EDF (Earliest Deadline First) to schedule the traffic from input ports to output ports on the router. Our simulations show that the router treats QoS (Quality of Service) traffic well.

  • 32.
    Kunert, Kristina
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Böhm, Annette
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Nordström, Tomas
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Providing Efficient Support for Real-Time Guarantees in a Fibre-Optic AWG-Based Network for Embedded Systems2017In: Optical Switching and Networkning Journal, ISSN 1573-4277, E-ISSN 1872-9770, Vol. 24, p. 47-56Article in journal (Refereed)
    Abstract [en]

    High-performance embedded systems running real-time applications demand communication solutions providing high data rates and low error probabilities, properties inherent to optical solutions. However, providing timing guarantees for deadline bound applications in this context is far from basic due to the parallelism inherent in multiwavelength networks and often bound to include a large amount of pessimism. Assuming deterministic medium access, an admission control algorithm using a schedulability analysis can ensure deadline guarantees for real-time communication. The traffic dependency analysis presented in this paper is specifically targeting a multichannel context, taking into consideration the possibility of concurrent transmissions in these types of networks. Combining our analysis with a feasibility analysis in admission control, the amount of guaranteed hard real-time traffic could be shown to increase by a factor 7 in a network designed for a radar signal processing case. Using this combination of analysis methods will render possible an increased amount of hard real-time traffic over a given multichannel network, leading to a more efficient bandwidth utilization by deadline dependent applications without having to redesign the network or the medium access method.

  • 33.
    Mahmood, Ali
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Böhm, Annette
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Embedded Systems (CERES).
    Wireless Sensor Networks for Surveillance Applications - A Comparative Survey of MAC Protocols2008In: Proceedings - The 4th International Conference on Wireless and Mobile Communications, ICWMC 2008, Piscataway, NJ.: IEEE Press, 2008, p. 399-403Conference paper (Refereed)
    Abstract [en]

    Wireless sensor nodes are made up of small electronic devices which are capable of sensing, computing and transmitting data from harsh physical environments. These sensor nodes depend on batteries for energy, which get depleted at a fast rate because of the computation and communication operations these nodes have to perform. A well designed MAC (Medium Access Control) protocol can prolong the network life. Aset of previously reported MAC layer protocols has abilities to achieve some energy efficiency. In this paper, we first describe some assumptions made for the specific application area of surveillance applications. Then, we compare a set of MAC protocols in terms of their suitability to be used in wireless sensor networks for this type of applications. In addition to energy efficiency, keeping the delays reasonably low is a crucial factor when sensing and reporting an event. © 2008 IEEE.

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